For today's complicated cellular networks Self Organising Network (SON) capabilities become essential in order to configure, organize, optimise performance and/or provide self-healing if/when faults occur. SON technology enables optimization of network performance and significant improvements in terms of capital expenditure (CAPEX) and operational expenditure (OPEX).
The major aspects of SON operation are self configuration, self optimization and self-healing. Self configuration enables access points (e.g. base stations, Node Bs, sectors (e.g. macrocells, picocells and femtocells), etc.) to become “Plug and Play” items. Once the system has been set up, operational characteristics of access points (APs) can be tuned, based on analyses of measurements data, thus enabling achievement of optimal network performance, coverage, and/or capacity by self-optimisation of the network. Self-optimization functions can include, for example, Load Balancing, Handover Optimization, Coverage & Capacity Optimization, Cell Outage Compensation, Energy Saving Management, etc. These optimization functions can change the coverage and capacity of a cell and, possibly, of surrounding cells, by configuring parameters (e.g. transmission power for downlink transmissions, antenna tilt, azimuth parameters, etc.) of the respective access point(s). Among the aspects addressed by the self-healing capability are detection of cell degradation and respective self-recovery of software, self-healing of board faults, cell outage recovery, and/or cell outage compensation, etc.
Typically, network optimization is as a process of improving the overall network quality, comprising improving a Quality of Service (QoS) indicative of a network's ability to provide given services with assured service level and/or improving a Quality of Experience (QoE) indicative of end users' level of satisfaction with given services. QoS can be evaluated with the help of Key Performance Indicators (KPIs) derived from data informative of network events and QoE can be evaluated with the help of Key Quality Indicators (KQIs) derived from data informative user-related events (optionally, the same data can be informative of both user related and network events). KPIs can characterize QoS of an entire network or parts thereof (e.g. one or more given access points or a group of access points, the group matching certain criteria, etc.). KQI can characterize QoE of one or more selected users, a user's segment matching certain criteria, etc.
Problems of operating self-organizing networks have been recognized in the conventional art and various techniques have been developed to provide solutions. For example:
US Patent Application No. 2007/280123 (Atkins, et al.) discloses a technique for testing, troubleshooting and evaluation of a mobile phone network. A method of processing network data includes a plurality of session related parameters. The method comprises inputting one or more queries, a query defining a statistic relating to said parameters and to be computed from said network data, formatting a query to define said statistic in terms of one or more intermediate statistics from which said statistic is computable, operating with said formatted query to determine said one or more intermediate statistics, and storing these in a data store for analysis, preferably indexed by said parameters. Entries for the parameters can be stored at time positions in a data pipe.
US Patent Application No. 2011/090820A (Hussein et al.) discloses a technique of optimizing a plurality of cell sites or sectors in a wireless network including receiving network data regarding a plurality of cell sites or sectors; determining a critical zone in which communication is degraded; determining best neighbor cell sites or sectors among the neighbor cell sites or sectors associated with the critical cell sites or sectors; determining if the critical cell sites or sectors in the critical zone have available resources for achieving a desired improvement in communications; determining if the best neighbor cell sites or sectors have available resources for achieving the desired improvement in communications; and altering wireless network parameters of the critical cell sites or sectors, or the best neighbor cells sites or sectors for achieving the desired improvement in communications. Altering wireless network parameters of the critical cell sites or sectors, or the best neighbor cell sites or sectors is performed continuously until the desired improvement in communications in the wireless network is achieved.
US Patent Application No. 2011/128890 (Schein et al.) discloses a technique of facilitating self-configuration and self-optimization of radio networks. An internal topology discovery is performed to assess characteristics of a plurality of access points within an internal network. An external cell discovery can also be performed to identify one or more access points operating within an external network. Based on the assessments obtained through the internal and/or external topology discovery processes, operational parameters are assigned to each access point within the internal network. Such operational parameters can include a transmit power associated with each radio node.
US Patent Application No. 2011/252123 (Sridhar et al.) discloses a self optimizing network wherein a policy and charging rules function (PCRF) includes an input port, a processor, and an output port. The input port receives near-real-time network state data. The processor makes optimization decisions based upon the near-real-time network state data. The processor also produces policy enforcement messages based upon the optimization decisions. The PCRF transmits the policy enforcement message via the output port.
US Patent Application No. 2011/136478 (Trigui) discloses a method of modifying communication parameters of a wireless network, the wireless network having, at least two antennas, and each of the antennas providing coverage to at least one sector. The method includes obtaining measurement data for at least two sectors of the wireless network, determining, from the obtained measurement data, if a signal strength indicator of one or more sectors of the at least two sectors is at or below a target value, determining, if the one or more sectors is at or below the target value, a communication parameter to be applied to the wireless network such that the signal strength indicator of the one or more sectors is above the target value, and modifying the communication parameters of the wireless network such that the determined communication parameter is applied to the wireless network.
US Patent Application No. 2012/142347 (Morad et al.) discloses a system for obtaining information relating to an idle mobile station in a cellular network. The system includes a computing platform which is in communication with a radio network controller of the cellular network. The computing platform is configured for (i) generating and sending an input signal through the radio network controller to the radio access network; and (ii) identifying in data outputted by the radio network controller an output signal resulting from the input signal, the output signal including information relating to at least one idle mobile station.
US Patent Application No. 2013/242720 (Chou) discloses a network management device and a method for coordination of self-optimization functions in a wireless network. A network management device for coordination of self-optimization functions includes one or more processors and an interface. The interface communicates with a plurality of enhanced node Bs (eNodeBs). The interface is arranged to receive a request to change a coverage or a capacity of an enhanced node B (eNodeB). The interface is further arranged to transmit a query to the eNodeB to obtain a self-optimizing network (SON) coordination state of the eNodeB. The one or more processors are arranged to determine whether to grant or deny the request based on a coordination policy and the SON coordination state.